package com.silentfish.practiceDemo.helper;

import com.silentfish.practiceDemo.util.CollectionUtil;
import com.silentfish.practiceDemo.util.PropsUtil;
import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;
import org.apache.commons.dbutils.handlers.MapListHandler;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Properties;

/**
 * 数据库操作助手类
 */
public class DatabaseHelper {//需要池化数据库连接
    private static final Logger LOGGER = LoggerFactory.getLogger(DatabaseHelper.class);

    private static final String DRIVER;
    private static final String URL;
    private static final String USERNAME;
    private static final String PASSWORD;
    private static final QueryRunner QUERY_RUNNER = new QueryRunner();
    private static final ThreadLocal<Connection> CONNECTION_HOLDER = new ThreadLocal<Connection>();

    static {
        Properties conf = PropsUtil.loadProps("config.properties");
        DRIVER = conf.getProperty("jdbc.driver");
        URL = conf.getProperty("jdbc.url");
        USERNAME = conf.getProperty("jdbc.username");
        PASSWORD = conf.getProperty("jdbc.password");

        try {
            Class.forName(DRIVER);
        }catch (ClassNotFoundException e){
            LOGGER.error("can not load jdbc driver",e);
        }
    }

    /**
     * 获取数据库连接
     */
    public static Connection getConnection(){
//        Connection conn = null;
        Connection conn = CONNECTION_HOLDER.get();
        try {
            conn = DriverManager.getConnection(URL,USERNAME,PASSWORD);
        }catch (SQLException e){
            LOGGER.error("get connection failure",e);
            throw new RuntimeException(e);//+
        }finally {
            CONNECTION_HOLDER.set(conn);//+
        }
        return conn;
    }

    /**
     * 关闭数据库连接
     */
    public static void closeConnection(){//Connection conn
        Connection conn = CONNECTION_HOLDER.get();
        if(conn != null){
            try {
                conn.close();
            }catch (SQLException e){
                LOGGER.error("close connection failure",e);
                throw new RuntimeException(e);
            }finally {
                CONNECTION_HOLDER.remove();//+
            }
        }
    }

    /**
     * 查询实体列表
     */
    public static <T> List<T> queryEntityList(Class<T> entityClass,String sql,Object... params){
        List<T> entityList;
        try {
            Connection conn = getConnection();
            entityList = QUERY_RUNNER.query(conn,sql,new BeanListHandler<T>(entityClass),params);
        }catch (SQLException e){
            LOGGER.error("query entityList failure",e);
            throw  new RuntimeException(e);
        }finally {
            closeConnection();//conn
        }
        return entityList;
    }

    /**
     * 查询实体
     */
    public static <T> T queryEntity(Class<T> entityClass,String sql,Object... params){
        T entity;
        try {
            Connection conn = getConnection();
            entity = QUERY_RUNNER.query(conn,sql,new BeanHandler<T>(entityClass),params);//BeanHandler<T>(entityClass)相当于mybatis返回值类型
        }catch (SQLException e){
            LOGGER.error("query entity failure",e);
            throw  new RuntimeException(e);
        }finally {
            closeConnection();//conn
        }
        return entity;
    }

    /**
     * 执行查询语句
     */
    public static List<Map<String,Object>> executeQuery(String sql, Object... params){
        List<Map<String,Object>> result;
        try {
            Connection conn = getConnection();
            result = QUERY_RUNNER.query(conn,sql,new MapListHandler(),params);
        }catch (SQLException e){
            LOGGER.error("execute query failure",e);
            throw  new RuntimeException(e);
        }finally {
            closeConnection();//conn
        }
        return result;
    }

    /**
     * 执行更新语句(包括update、insert、delete)
     */
    public static int executeUpdate(String sql, Object... params){
        int rows = 0;
        try {
            Connection conn = getConnection();
            rows = QUERY_RUNNER.update(conn,sql,params);
        }catch (SQLException e){
            LOGGER.error("execute update failure",e);
            throw  new RuntimeException(e);
        }finally {
            closeConnection();//conn
        }
        return rows;
    }

    /**
     * 插入实体 --自写-无需知道表字段顺序
     */
    public static <T> boolean insertEntity(Class<T> entityClass,Map<String,Object> fieldMap){
        if(CollectionUtil.isEmpty(fieldMap)){
            LOGGER.error("can not insert entity: fieldMap is empty");
            return false;
        }

        String sql = "INSERT INTO " + gettableName(entityClass);
        StringBuilder columns = new StringBuilder();
        StringBuilder columnValues = new StringBuilder();

        for (String fieldName : fieldMap.keySet()){
            columns.append(fieldName).append(", ");
            columnValues.append("?, ");
        }

        sql = sql + " (" + columns.substring(0,columns.lastIndexOf(", ")) + ") "
                + "VALUES(" + columnValues.substring(0,columns.lastIndexOf(", "))+ ")";

        List<Object> paramList = new ArrayList<Object>();
        paramList.addAll(fieldMap.values());
        Object[] params = paramList.toArray();

        return executeUpdate(sql,params) == 1;
    }

    /**
     * 更新实体
     */
    public static <T> boolean updateEntity(Class<T> entityClass,long id,Map<String,Object> fieldMap){
        if(CollectionUtil.isEmpty(fieldMap)){
            LOGGER.error("can not update entity: fieldMap is empty");
            return false;
        }

        String sql = "UPDATE " + gettableName(entityClass) + " SET";
        StringBuilder columns = new StringBuilder();

        for (String fieldName : fieldMap.keySet()){
            columns.append(fieldName).append("=?, ");
        }

        sql += columns.substring(0,columns.lastIndexOf(", ")) + " WHERE id =?";

        List<Object> paramList = new ArrayList<Object>();
        paramList.addAll(fieldMap.values());
        paramList.add(id);
        Object[] params = paramList.toArray();

        return executeUpdate(sql,params) == 1;
    }
    /**
     * 删除实体  --自写
     */
    public static <T> boolean deleteEntity(Class<T> entityClass,long id){
        String sql = "DELETE FROM " + gettableName(entityClass) + "  WHERE id =?";

        List<Object> paramList = new ArrayList<Object>();
        paramList.add(id);
        Object[] params = paramList.toArray();

        return executeUpdate(sql,params) == 1;
    }

    /**
     * 获取表名
     */
    private static String gettableName(Class<?> entityClass){
        return entityClass.getSimpleName();
    }
}




